The present invention relates to a continuously variable transmission and more particularly to a fluid flow path structure of a continuously variable transmission.
JP-U 58-67158 discloses a continuously variable transmission. In this known continuously variable transmission, passages are formed in a side cover of a casing and define a part of a fluid flow path conducting oil to and from a fluid pressure chamber of a follower pulley. The oil from this passage os the side cover is supplied to the fluid pressure chamber of the follower pulley via an axial passage formed in a follower shaft. The passages of the side cover are composed of a plurality of bores which are formed by casing or machining.
This known fluid flow path structure results in an increase in overall axial dimension of the continuously variable transmission, posing a problem that it becomes difficult to install the continously variable transmission in a smaller sized vehicle. The fluid flow path is composed of bores formed by casting and machining, so that the side cover has to be formed with an increased thickness portion which such bores are formed through. This causes an axial expansion of the side cover, resulting in an increase in overall axial dimension of the continuously variable transmission. Particularly, that portion of the side cover which is positioned near the follower pulley has to be mounted near a vehicle body member, so that the expansion of this portion of the side cover makes it very difficult to install the continuously variable transmission in a smaller sized vehicle.
An object of the present invention is to provide a continuously variable transmission with an unique fluid flow path whereby the axial overall dimension of the transmission is reduced.